/*
 * Copyright (c) OSGi Alliance (2008). All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.osgi.service.threadio;

import java.io.InputStream;
import java.io.PrintStream;

/**
 * Enable multiplexing of the standard IO streams for input, output, and error.
 * 
 * This service guards the central resource of IO streams. The standard streams
 * are singletons. This service replaces the singletons with special versions
 * that can find a unique stream for each thread. If no stream is associated
 * with a thread, it will use the standard input/output that was originally set.
 * 
 * TODO The javadoc in this class need a good scrub before release.
 * 
 * @ThreadSafe
 * @version $Revision: 5654 $
 */
public interface ThreadIO {
	/**
	 * Associate this streams with the current thread.
	 * 
	 * Ensure that when output is performed on System.in, System.out, System.err it
	 * will happen on the given streams. 
	 * 
	 * The streams will automatically be canceled when the bundle that has gotten
	 * this service is stopped or returns this service.
	 * 
	 * @param in InputStream to use for the current thread when System.in is used
	 * @param out PrintStream to use for the current thread when System.out is used
	 * @param err PrintStream to use for the current thread when System.err is used
	 */
	void setStreams(InputStream in, PrintStream out, PrintStream err);

	/**
	 * Cancel the streams associated with the current thread.
	 * 
	 * This method will not do anything when no streams are associated.
	 */
	void close();
}
